In the case of \(b_j=0\) , \(1\le j \le d\) , the same result is proved in
[1]} and we can refer also to [2]}. However, it seems no proofs
for a non-symmetric elliptic operator \(A\) , although one naturally expect
the same continuity.
The proof is typical as arguments by the operator theory applied to
the classical
partial differential equations and we carry out similar arguments for
fractional differential equations within our framework.
